Computer modeling of a-SiC:H/a-Si:H heterojunction solar cell performance as a function of the apportionment of the bandgap discontinuity

A computer-model study is used to investigate the effects of the distribution of the bandgap discontinuity in a-SiC:H/a-Si:H heterojunction p-i-n solar cells. It is found that the influence of the energy location of the p-layer/i-layer bandgap discontinuity on cell performance is strongly dependent on the acceptor doping density in the p-layer and the gap state densities in both the p-layer and the p/i interface region. If all the bandgap discontinuity appears in valence band, then achieving the best performance requires high values of the acceptor doping density. If the discontinuity is equally shared between the bands, then only moderate doping in the p-region is required. If the bandgap discontinuity is entirely in the conduction band, then lower doping can be tolerated